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My goal with this function is to verify the input; in this case, to verify if the candidate is correct. To do that, I tried a for loop that verifies if the candidate is equal to the input, and then it adds a vote to it. After that, what I want is to return a true value of the function, but if that does not happen the function should return a false value. The problem is that the function only returns false values, no matter the input.

Here is the code

#include <cs50.h>
#include <stdio.h>
#include <string.h>

// Max number of candidates
#define MAX 9

// Candidates have name and vote count
typedef struct
{
    string name;
    int votes;
}
candidate;

// Array of candidates
candidate candidates[MAX];

// Number of candidates
int candidate_count;

// Function prototypes
bool vote(string name);
void print_winner(void);

int main(int argc, string argv[])
{
    // Check for invalid usage
    if (argc < 2)
    {
        printf("Usage: plurality [candidate ...]\n");
        return 1;
    }

    // Populate array of candidates
    candidate_count = argc - 1;
    if (candidate_count > MAX)
    {
        printf("Maximum number of candidates is %i\n", MAX);
        return 2;
    }
    for (int i = 0; i < candidate_count; i++)
    {
        candidates[i].name = argv[i + 1];
        candidates[i].votes = 0;
    }

    int voter_count = get_int("Number of voters: ");

    // Loop over all voters
    for (int i = 0; i < voter_count; i++)
    {
        string name = get_string("Vote: ");

        // Check for invalid vote
        if (!vote(name))
        {
            printf("Invalid vote.\n");
        }
    }

    // Display winner of election
    print_winner();
}

// Update vote totals given a new vote
bool vote(string name)
{
    for(int i = 0; i< candidate_count; i++)
    {
        if(strcmp(candidates[i].name, name) == true)
        {
            candidates[i].votes = candidates[i].votes + 1;
            return true;
        }
    }
    return false;
}


// Print the winner (or winners) of the election
void print_winner(void)
{
    return;
}

The output is always:

./plurality Bob Joe Bill
Number of voters: 3
Vote: Joe
Invalid vote.
Vote: Bill
Invalid vote.
Vote: Bob
Invalid vote.
Jonathan Leffler
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Renato2022
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    Function `strcmp` does not return `true`, but either [negative, 0, or positive](https://en.cppreference.com/w/c/string/byte/strcmp) depending upon the result. So try changing `true` to `0` at the condition in the `vote` function. – Paul T. Jul 31 '22 at 03:22
  • Have you tried printing the invalid name: `printf("Invalid vote (for [[%s]])\n", name);`? This might show you that there is a problem with the name, such as a trailing newline included. But @PaulT.'s observation is more relevant — you are misinterpreting the result from `strcmp()`. For equality, `strcmp(a, b) == 0` is the correct test. Indeed, you should always compare with `0`, and use the operator for the comparison you're after: `strcmp(a, b) > 0` for "`a` greater than (sorts after) `b`", `strcmp(a, b) >= 0` for "`a` greater than or equal to `b`", etc. – Jonathan Leffler Jul 31 '22 at 03:23
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    @PaulT. that's incorrect. `strcmp` returns [negative, 0 or positive](https://en.cppreference.com/w/c/string/byte/strcmp) and not -1/0/1. [When will strcmp not return -1, 0 or 1?](https://stackoverflow.com/q/13571907/995714). cplusplus.com has some incorrect information and is discouraged here – phuclv Jul 31 '22 at 03:24
  • @phuclv ... ok that is good to know going forward, thanks! ... I updated that comment, and with a different link reference. – Paul T. Jul 31 '22 at 03:25

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